How to make the webpage automatically refresh every 5 seconds

void loop() {

  // listen for incoming clients
  WiFiClient client = server.available();

  if (client) {
    Serial.println("new client");
    // an http request ends with a blank line
    boolean currentLineIsBlank = true;
    while (client.connected()) {
      if (client.available()) {
        char c = client.read();// Read char by char HTTP request
        readString += c;
        Serial.write(c);

        // if you've gotten to the end of the line (received a newline
        // character) and the line is blank, the http request has ended,
        // so you can send a reply
        if (c == '\n' && currentLineIsBlank) {
          // send a standard http response header
          client.println("HTTP/1.1 200 OK");
          client.println("Content-Type: text/html");
          client.println("Connection: close");  // the connection will be closed after completion of the response
          //client.println("Refresh: 5");  // refresh the page automatically every 5 sec
          client.println();
          client.println("<!DOCTYPE HTML>");
          client.println("<head><title>WiFi Sensor</title></head>");
          client.println("<center><hr/><p> Click the Buttons to view the charge point. <p/><hr/></center>");
          client.println("<center><input type=button value='Detect' onmousedown=location.href='/?DETECT'></center><hr/>");
          if (distance<= 200) {
            client.println("<center><hr/><p> Occupied. <p/><hr/></center>");
          } else {
            client.println("<center><hr/><p> Unoccupied. <p/><hr/></center>");
          }
          client.println("<hr/>");
          client.println("</body>");
          client.println("</html>");
          break;
        }
        if (c == '\n') {
          // you're starting a new line
          currentLineIsBlank = true;
        }
        else if (c != '\r') {
          // you've gotten a character on the current line
          currentLineIsBlank = false;
        }
      }
    }
    // give the web browser time to receive the data
    delay(1);

    // close the connection:
    client.stop();
    if (readString.indexOf("/?DETECT") > 0) {
      Serial.println();
      Serial.println("DETECT");
      Serial.println();
      detect();
    }
    readString = "";// Clearing string for next read
    Serial.println("client disconnected");
  }
}

How to make it refresh every 5 secs?

uncomment the line
//client.println("Refresh: 5"); // refresh the page automatically every 5 sec

         client.println("Content-Type: text/html");
          client.println("Connection: close");  // the connection will be closed after completion of the response
          //client.println("Refresh: 5");  // refresh the page automatically every 5 sec
          client.println();
          client.println("<!DOCTYPE HTML>");

At a quick glance your refresh header is commented out. That might be because you are having some other problem, but thought I'd mention it in the event you hadn't noticed.

freaklabs:
Has this issue been solved? If so, can you post the solution?

see comment #1